Heretofore chairs usually had frames for seat and legs that were rigid both in structure and attachment of component parts. This meant that chairs had to have thick cushioning in the seat and back areas if resilient comfort was desired, or a sacrifice of comfort was made through the use of a seat and back of hard materials such as sheet metal, plywood or rigid plastic.
Another shortcoming of previous chair and seat designs was that they incorporated backs incapable of fitting a range of sitters's sizes and forms. If the back was comfortable for a large person, it was not for a small person, and vice versa. Many attempts were made to provide back height and angle adjustment but these required the sitter to know how to operate the adjusting mechanisms as well as to know what the most ideal configuration of the chair should be for a person of his size and form, something only an expert orthopedist would know.
Previously, upholstery on chairs was usually tacked or stapled on permanently, and removal for cleaning was very inconvenient and often impossible for a non-expert. Such chairs were seldom properly cleaned. Reupsholstering also required experts and often cost nearly as much as the initial total price of the chair. Sometimes stretch fabrics were used but those were susceptible to easy pricking by sharp objects and would unravel, sometimes similarly to ladies' hose, and would not wear as long as conventional non-stretch fabrics.
Heretofore, few chair frames were readily separable from leg structures, and those that were required unsightly screws to attach the seat and back elements to the frame. Also, previous chair frame structures have usually been rigid in a manner which caused the chair to wobble or tip on uneven floor surfaces.
No seat-back or chair design has provided workable solutions to these problems, until the present invention described below.